High temperature combustion is often employed in many industrial processes, such as glassmelting and waste incineration. The burners used to carry out such processes often utilize liquid fuel, such as oil. U.S. Pat. No. 4,541,796, for example, describes a burner having at least two passageways for delivering liquid fuel and oxidant separately to a point outside of the burner. The liquid fuel delivered separately is initially atomized and is then mixed and combusted with the oxidant. Atomization of liquid fuel is necessary for effective combustion.
U.S. Pat. No. 4,738,614 describes an atomizer useful for, inter alia, those burners described and claimed in U.S. Pat. No. 4,541,796. The atomizer has a specifically designed liquid fuel passageway and an angular atomizing fluid port. While the liquid fuel is injected through the liquid fuel passageway, atomizing fluid is introduced to the fuel passageway at an angle of 45 to 75 degrees, preferably at an angle of 60 degrees, measured from the longitudinal axis of the fuel passageway, through the angular atomizing fluid port. This atomizer is indicated to be superior to known pressure and mechanical atomizers in avoiding problems, such as mechanical break down of moving parts or plugging of very small liquid fuel orifices.
This atomizer, however, suffers from certain drawbacks. First, the control of liquid fuel flow is difficult since the atomizer is designed in such a manner that there is a pressure dependence between the liquid fuel and the atomizing fluid. Increasing the flow of the atomizing fluid, for example, causes an increased back pressure on the liquid fuel supply whereby the flow control of liquid fuel supply is made difficult. Second, this atomizer cannot be operated effectively, when it is recessed within a refractory port of the furnace wall. The atomized fuel stream, such as oil, impinges on the inside surface of the refractory port, causing the formation of soot within the port, thus fouling the atomizer and the port. Finally, this atomizer may cause unsafe combustion if the atomizing fluid employed contains oxygen. Because the liquid fuel is internally atomized within the fuel passageway with a fluid fuel atomizing fluid, the liquid fuel may flow into the atomizing fluid (oxygen) line, thus causing unsafe combustion.
It is therefore an object of the invention to provide an atomizing means useful for effectively controlling the flow of liquid fuel.
It is another object of the invention to provide an atomizing means that can be used effectively in atomizing and combusting liquid fuel without fouling the atomizing means even when it recessed within a refractory port of the furnace wall.
It is yet another object of the invention to provide an atomizing means which can utilize atomizing fluid containing oxygen with the minimal risk of unsafe combustion.
It is an additional object of the invention to provide an atomizing means which can be incorporated into a burner capable of operating without any water cooling means.